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Abstract:

Rotary switch interlock mechanisms and electrical switch assemblies with
a rotary switch interlock mechanism are presented herein. An electrical
distribution device with at least two electrical switches is disclosed.
Each of the electrical switches has a switch actuator that is movable
between engaged and disengaged positions. A rotary interlock member is
rotatably mounted to the housing of the electrical distribution device
adjacent the first and second electrical switches. The rotary interlock
member is rotatable 180 degrees between a first orientation, whereat the
rotary member allows the switch actuator of the second electrical switch
into its engaged position while preventing the switch actuator of the
first electrical switch from being moved into its engaged position, and a
second orientation, whereat the rotary member allows the first switch
actuator to be moved into its engaged position while preventing the
second switch actuator from being moved into its engaged position.

Claims:

1. An electrical distribution device for distributing power to a load,
the electrical distribution device comprising: a housing; first and
second electrical switches operatively attached to the housing, each of
the electrical switches having a respective switch actuator movable
between respective engaged and disengaged positions; and a rotary member
rotatably mounted to the housing adjacent the switch actuators of the
first and second electrical switches, the rotary member having a body
with a receiving portion and a blocking portion, wherein the rotary
member is rotatable between a first orientation, whereat the blocking
portion prevents one of the switch actuators from being moved into the
engaged position and the receiving portion receives the other one of the
switch actuators when moved into the engaged position, and a second
orientation, whereat the blocking portion prevents the other one of the
switch actuators from being moved into the engaged position and the
receiving portion receives the one of the switch actuators when moved
into the engaged position.

2. The electrical distribution device of claim 1, wherein the rotary
member body is disk-shaped and rotatably mounted to the housing in
between the switch actuators of the first and second electrical switches.

3. The electrical distribution device of claim 2, wherein a diameter of
the disk-shaped body is greater than a distance between the switch
actuators of the first and second electrical switches.

4. The electrical distribution device of claim 1, wherein the receiving
portion is a slot defined on an outer peripheral portion of the rotary
member body, the slot being configured to receive therein the switch
actuator of the second electrical switch when the rotary member is in the
first orientation, and receive therein the switch actuator of the first
electrical switch when the rotary member is in the second orientation.

5. The electrical distribution device of claim 1, wherein the rotary
member body has opposing first and second sides, the receiving portion
being a slot defined by the first side of the body, the slot being
configured to individually receive therein the switch actuators, and the
blocking portion being a blocking wall on the second side of the rotary
member body, the blocking wall being configured to physically obstruct
the engaged positions of the switch actuators.

6. The electrical distribution device of claim 5, wherein, when the
rotary member is in the first orientation, the blocking wall blocks the
switch actuator of the first electrical switch from being moved into the
respective engaged position and the slot receives therein the switch
actuator of the second electrical switch when moved into the respective
engaged position, and when the rotary member is in the second
orientation, the blocking wall blocks the switch actuator of the second
electrical switch from being moved into the respective engaged position
and the slot receives therein the switch actuator of the first electrical
switch when moved into the respective engaged position.

7. The electrical distribution device of claim 1, wherein the position of
the rotary member relative to the housing remains unchanged when the
rotary member rotates between the first and second orientations.

8. The electrical distribution device of claim 1, wherein the rotary
member includes one or more protrusions projecting from a surface of the
disk, the protrusions being configured to facilitate rotating the rotary
member between the first and second orientations.

9. The electrical distribution device of claim 1, further comprising a
rivet configured to rotatably mount the rotary member to the housing.

10. The electrical distribution device of claim 1, further comprising a
mounting bracket configured to rotatably mount the rotary member to the
housing.

11. The electrical distribution device of claim 1, wherein each of the
switch actuators of the first and second electrical switches includes a
toggle switch.

12. The electrical distribution device of claim 1, consisting essentially
of the rotary member and a rivet configured to rotatably mount the rotary
member to the housing.

13. A circuit breaker assembly for selectively connecting different power
sources to a load, the circuit breaker assembly comprising: first and
second circuit breakers operatively mounted to a switch panel in-line and
opposed to one another, each of the circuit breakers being mounted in a
respective one of two columns on either side of a medial line between the
circuit breakers, each of the circuit breakers having a respective handle
having respective ON and OFF handle positions, wherein the ON handle
positions of the opposed circuit breakers pivot toward the medial line,
and the OFF handle positions of the opposed circuit breaker pivot away
from the medial line; and a rotating disk mounted in between the handles
of the first and second circuit breakers, an outer peripheral portion of
the rotating disk defining a slot centered at a zero degree point on the
circumference of the rotating disk, the slot being shaped and sized to
receive therein one of the breaker handles, another outer peripheral
portion of the rotary member at a 180 degree point on the circumference
of the disk being sans a slot capable of receiving therein one of the
breaker handles, whereby the rotating disk can be placed in a position
where only a selected one of the first and second circuit breaker handles
can be moved into the ON position at one time while a non-selected one of
the first and second circuit breaker handles is prevented from being
moved into the ON position.

14. A circuit breaker assembly for selectively connecting different power
sources to a load, the circuit breaker assembly comprising: a housing
with a switch panel; a first circuit breaker mounted to the switch panel,
the first circuit breaker having a first toggle switch movable along a
common plane from a first engaged position, whereat the first circuit
breaker electrically couples a first power source to the load, and a
first disengaged position, whereat the first circuit breaker disconnects
the first power source from the load; a second circuit breaker mounted to
the switch panel adjacent the first circuit breaker, the second circuit
breaker having a second toggle switch in-line with and opposing the first
toggle switch, the second toggle switch being movable along the common
plane from a second engaged position, whereat the second circuit breaker
electrically couples a second power source to the load, and a second
disengaged position, whereat the second circuit breaker disconnects the
second power source from the load; and a rotary interlock mechanism
having a disk-shaped body rotatably mounted to the switch panel
intermediate the first and second toggle switches, the disk-shaped body
having opposing first and second sides, the first side of the disk-shaped
body defining a slot configured to individually receive therein the first
and second toggle switches, and the second side having a blocking wall
configured to physically obstruct the first and second engaged positions,
wherein the rotary interlock mechanism is selectively rotatable between a
first orientation, whereat the blocking wall blocks the first toggle
switch from being moved into the first engaged position and the slot
receives therein the second toggle switch when moved into the second
engaged position, and a second orientation, whereat the blocking wall
blocks the second toggle switch from being moved into the second engaged
position and the slot receives therein the first toggle switch when moved
into the first engaged position.

Description:

FIELD OF THE INVENTION

[0001] The present disclosure relates generally to electrical distribution
devices with multiple switches, such as circuit breakers. More
particularly, the present disclosure relates to switch interlock
mechanisms for preventing two functionally paired switches in an
electrical distribution device from being engaged at the same time.

BACKGROUND

[0002] In electronics, a switch is an electrical component that can break
an electrical circuit, for example, to interrupt the current flow or
divert the current from one electrical path to another. One type of
electrical switch is the circuit breaker, which is an automatically
operated electrical switch designed to electrically engage and disengage
a selected circuit from an electrical power supply, for example, to
protect the circuit from damage that can be caused by an overload or a
short circuit. In general, a circuit breaker detects a fault condition,
such as an overcurrent condition, and responsively discontinues
electrical flow (i.e., "trips the circuit"), which is typically achieved
by opening operating contacts within the circuit breaker to interrupt the
current flow. To resume normal operation, the circuit breaker can
normally be reset, either manually or automatically. Circuit breakers are
manufactured in various sizes and configurations, from small safety
breakers that protect an individual household appliance up to large
switchgear designs for protecting high voltage circuits which distribute
electricity to an entire town.

[0003] In many electrical supply systems, there are applications where a
circuit must switch between alternate sources of electric power. For
instance, many commercial buildings, residential homes, and industrial
facilities need the capacity to switch from a standard utility power
source to a back-up power generator. A common application of this type of
arrangement is known as a "transfer switch." To support these
applications, some circuit breaker boxes are designed with separate
electrical circuits that are arranged so that when one group of circuits
is switched to a conductive state, another group of circuits is switched
to a non-conductive state in alternating fashion. In some arrangements, a
common load can be alternately switched between separate power sources so
that as one power source is disconnected from the load the second power
source is connected after a negligible delay.

[0004] In many common circuit breaker box designs, the individual breaker
switches are packaged such that switches that are connectable to related
circuits are arranged in horizontally or vertically opposing in-line
pairs. To accomplish a switching operation, such as those described
above, one switch is flipped (opened or closed) before a second switch of
a functional pair is flipped (closed or opened). In a transfer switch
application where the breaker switches are manually operated, the
operator will flip the transfer switches by hand, first disconnecting the
utility current source from the circuit and then connecting the back-up
generator to the circuit (and vice versa). Manually operated breaker
switches are typically spring biased so that once a switch handle has
reached top dead-center, any slight deflection from that position will
cause the switch to continue to the fully switched position, unless
otherwise restrained.

[0005] Separately acting switches are used in safety circuit breaker
assemblies to ensure that the utility current circuitry is disengaged
before a separate power source is connected, thereby preventing
electricity from being fed back into the utility circuit. In addition,
interlock mechanisms have been created that prevent one switch, which
engages a first power source, from being closed at the same time a second
switch in a functional pair, which engages another power source, is
closed. Most interlock mechanisms are comprised of a slidably mounted
blocking plate that can be moved rectilinearly between two operating
positions. When in the first operating position, the blocking plate
prevents a first switch handle from being closed while permitting a
second switch handle to be closed. The blocking plate can then be slid to
the second operating position, whereat the plate prevents the second
switch handle from being closed while allowing the first switch handle to
be closed.

[0006] Prior art switch interlock mechanisms for in-line opposed switches
tend to be unnecessarily complex mechanisms, requiring a large number of
components and moving parts to provide the blocking feature. The
complexity of such devices increases manufacturing and assembly costs,
and creates a higher likelihood of warranty claims for broken devices. In
addition, a large amount of packaging space is consumed to accommodate
the linear movement of the blocking plate, namely the multiple operating
positions. Thus, there is a need for electrical switch interlock
mechanisms that prevent multiple switches in a functional group from
being engaged at the same time, while not requiring a large number of
components or a lot of packaging space to properly operate.

SUMMARY

[0007] Rotary interlock mechanisms are disclosed herein that require very
few parts, and are therefore inexpensive to manufacture and easy to
install. Rotary interlock mechanisms are disclosed herein that feature an
ergonomic design that minimizes physical effort and discomfort, and hence
maximizes efficiency. Rotary interlock mechanisms are disclosed herein
that are completely secure, ensuring that blocked switches are kept
disconnected while allowing unblocked switches to be easily
connected--i.e., there is no possibility to activate both switches at the
same time. Rotary interlock mechanisms are disclosed herein that minimize
the amount of packaging space required to properly operate. Rotary
interlock mechanisms are disclosed herein that do not require any
additional/special tooling to move the mechanism. Rotary interlock
mechanisms are disclosed herein that require special tooling to remove
the mechanism.

[0008] According to some aspects of the present disclosure, an electrical
distribution device for distributing power to a load is presented. The
electrical distribution device includes at least two electrical switches
that are operatively attached to a housing. Each of the electrical
switches has a respective switch actuator that is movable between a
respective engaged position and a respective disengaged position. A
rotary member is rotatably mounted to the housing adjacent the switch
actuators of the first and second electrical switches. The rotary member
has a body with a receiving portion and a blocking portion. The rotary
member is rotatable between first and second orientations. When in the
first orientation, the blocking portion prevents one of the switch
actuators from being moved into its engaged position, whereas the
receiving portion receives the other switch actuator allowing it to be
moved into its engaged position. In contrast, when the rotary member is
in the second orientation, the blocking portion prevents the other switch
actuator from being moved into its engaged position, and the receiving
portion receives the one switch actuator allowing it to be moved into its
engaged position.

[0009] According to other aspects of the present disclosure, a circuit
breaker assembly is featured for selectively connecting different power
sources to a load. The circuit breaker assembly includes first and second
circuit breakers that are operatively mounted to a switch panel in-line
and opposed to one another. Each of the circuit breakers is mounted in a
respective one of two columns on either side of a medial line between the
circuit breakers. Each of the circuit breakers has a respective handle
having respective ON and OFF handle positions. The ON handle positions of
the opposed circuit breakers pivot toward the medial line, whereas the
OFF handle positions of the opposed circuit breaker pivot away from the
medial line. A rotating disk is mounted in between the handles of the
first and second circuit breakers. An outer peripheral portion of the
rotating disk has a slot centered at a zero degree point on the
circumference of the rotating disk. The slot is shaped and sized to
receive therein one of the breaker handles. Another outer peripheral
portion of the rotary member at a 180 degree point on the circumference
of the disk is sans a slot capable of receiving therein one of the
breaker handles. The rotating disk can be placed in a position where only
a selected one of the first and second circuit breaker handles can be
moved into the ON position at one time, while a non-selected one of the
first and second circuit breaker handles is prevented from being moved
into the ON position.

[0010] According to other aspects of the present disclosure, a circuit
breaker assembly is presented for selectively connecting different power
sources to a load. The circuit breaker assembly includes a housing with a
switch panel. First and second circuit breakers are mounted to the switch
panel adjacent one another. The first circuit breaker has a first toggle
switch that is movable along a common plane from a first engaged
position, whereat the first circuit breaker electrically couples a first
power source to the load, and a first disengaged position, whereat the
first circuit breaker disconnects the first power source from the load.
The second circuit breaker has a second toggle switch that is movable
along the common plane from a second engaged position, whereat the second
circuit breaker electrically couples a second power source to the load,
and a second disengaged position, whereat the second circuit breaker
disconnects the second power source from the load. The circuit breaker
assembly also includes a rotary interlock mechanism having a disk-shaped
body that is rotatably mounted to the switch panel intermediate the first
and second toggle switches. The disk-shaped body has opposing first and
second sides, the first side of the disk-shaped body defining a slot
configured to individually receive therein the first and second toggle
switches. The second side has a blocking wall configured to physically
obstruct the first and second engaged positions. The rotary interlock
mechanism is selectively rotatable between a first orientation, whereat
the blocking wall blocks the first toggle switch from being moved into
the first engaged position and the slot receives therein the second
toggle switch when moved into the second engaged position, and a second
orientation, whereat the blocking wall blocks the second toggle switch
from being moved into the second engaged position and the slot receives
therein the first toggle switch when moved into the first engaged
position.

[0011] The above summary is not intended to represent each embodiment or
every aspect of the present disclosure. Rather, the foregoing summary
merely provides an exemplification of some of the novel features
disclosed herein. The above features and advantages, and other features
and advantages of the present disclosure, will be readily apparent from
the following detailed description of the exemplary embodiments and best
modes for carrying out aspects of the present invention when taken in
connection with the accompanying drawings and appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 is an elevated perspective-view illustration of a
representative electrical switch assembly with an exemplary rotary
interlock mechanism in accordance with embodiments of the present
disclosure.

[0013]FIG. 2 is a perspective-view illustration of a portion of a
representative circuit breaker assembly with another exemplary rotary
interlock mechanism in accordance with embodiments of the present
disclosure.

[0014]FIG. 3 is a plan-view illustration of another representative
circuit breaker assembly with another exemplary rotary interlock
mechanism in accordance with embodiments of the present disclosure.

[0015]FIG. 4 is an exploded perspective-view illustration of an exemplary
rotary interlock mechanism in accordance with embodiments of the present
disclosure.

[0016] While the present disclosure is susceptible to various
modifications and alternative forms, specific embodiments have been shown
by way of example in the drawings and will be described in detail herein.
It should be understood, however, that the disclosure is not intended to
be limited to the particular forms disclosed. Rather, the disclosure is
to cover all modifications, equivalents, and alternatives falling within
the spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION

[0017] Referring now to the drawings, wherein like reference numerals
refer to like components throughout the several views, FIG. 1 illustrates
an exemplary electrical switch assembly, designated generally as 10, with
an exemplary rotary interlock mechanism, designated generally as 12, in
accordance with embodiments of the present disclosure. It should be
understood that the drawings are not necessarily to scale and are
provided purely for descriptive purposes; thus, the individual and
relative dimensions of the drawings presented herein are not to be
considered limiting. Likewise, many of the disclosed concepts are
discussed with reference to electrical circuit breaker assemblies;
however, the concepts of the present disclosure are not so limited and
are just as applicable to any electrical switch assembly having at least
two electrical switches. Turning then to FIG. 1, the electrical switch
assembly 10 generally includes a housing, designated generally as 14,
having a top wall 16 that extends between and connects first and second
opposing side walls 18 and 20, respectively. The housing walls 16, 18, 20
cooperate to define an open interior within which is mounted a power
distribution base assembly, designated generally as 22 in FIG. 1, which
is operable for distributing electricity.

[0018] A switch panel 24 extends through an opening in the top wall 16 of
the housing 14. A pair of electrical switches, such as first and second
circuit breakers 26 and 28, respectively, are mounted to the housing 14.
The first circuit breaker 26 includes a switch actuator, presented in the
form of a first toggle switch 30, which is movable between respective
engaged and disengaged positions. The second circuit breaker 28 also
includes a switch actuator, which is presented in the form of a second
toggle switch 32, that is movable between respective engaged and
disengaged positions. In the illustrated embodiment, the first and second
circuit breakers 26, 28 are mounted adjacent one another such that the
first and second toggle switches 30, 32 are operatively aligned along a
common plane (shown for illustrative purposes at 34) in spaced relation
to one another for pivoting in a substantially parallel manner between
respective engaged and disengaged positions. When in the first engaged
position, the first toggle switch 30 pivots along the common plane 34
towards the second toggle switch 32 (i.e., generally to the right in FIG.
1), and pivots away from the second toggle switch 32 (i.e., generally to
the left in FIG. 1) when in the first disengaged position. By way of
comparison, the second toggle switch 32 pivots towards the first toggle
switch 30 (i.e., generally to the left in FIG. 1) when in the second
engaged position, and pivots away from the first toggle switch 30 (i.e.,
generally to the right in FIG. 1) when in the second disengaged position.

[0019] The number, orientation, and means for activating the electrical
switches may be varied, individually, collectively, and in any
combination, from what is shown in FIG. 1 without departing from the
intended scope and spirit of the present disclosure. For instance, the
rotary interlock mechanism 12 may be readily modified to functionally
operate with more than two switches, as discussed in further derail
below. Moreover, each of the electrical switches may be activated by
means other than a toggle switch, such as a push-button switch or a
rocker switch. To that end, the toggle switches need not be operatively
aligned along a common plane for pivoting between respective engaged and
disengaged positions; rather, the toggle switches may be angularly offset
from one another.

[0020] According to some configurations, the electrical switch assembly 10
operates as a transfer switch. In this instance, the first breaker switch
26 can be a primary main breaker, which is movable between ON and OFF
positions: when in the engaged or ON position, the primary main breaker
distributes power from a primary power source, such as a standard utility
power source, to a load; and, when in the disengaged or OFF position, the
primary main breaker functions to cut off the supply of power from the
primary power source. The second breaker switch 28 can be an auxiliary
main breaker, which is movable between ON and OFF positions: when in the
engaged or ON position, the auxiliary main breaker distributes power from
an auxiliary power source, such as a back-up power generator, to the
load; and, when in the disengaged or OFF position, the auxiliary main
breaker functions to cut off the supply of power from the auxiliary power
source.

[0021] In accordance with an aspect of the present disclosure, the
electrical switch assembly 10 also includes a rotary interlock mechanism
12. In general, the rotary interlock mechanism 12 includes a rotary
member 40 that is configured to rotatably mount to the housing 14
adjacent the first and second electrical switches 26, 28 to allow only
one of the switches 26, 28 to be moved into the ON position at one time.
In the present embodiment, it will be appreciated that both of the
switches can be in the OFF position at one time (see, e.g., FIG. 2). The
rotary member 40 is rotatable between a first orientation, which may be
denominated zero degrees, whereat the rotary member 40 prevents the
switch actuator 30 of the first electrical switch 26 from being moved
into the first engaged position, and a second orientation, which may be
denominated 180 degrees, whereat the rotary member prevents the switch
actuator 32 of the second electrical switch 28 from being moved into the
second engaged position. When in the first orientation, the rotary member
40 only allows the switch actuator 32 of the second electrical switch 28
to be moved into its engaged position. In contrast, when in the second
orientation, the rotary member 40 only allows the switch actuator 30 of
the first electrical switch 26 to be moved into its engaged position.

[0022] In the illustrated example, the rotary interlock mechanism 40 has a
disk-shaped body that is rotatably mounted to the bracket 50, e.g., via
fastener 42, approximately halfway between the first and second toggle
switches 30, 32. As seen in FIG. 1, the outer-most diameter of the
disk-shaped body is greater than the distance between the first and
second toggle switches 30, 32. The disk-shaped body has opposing first
and second sides; the first side of the disk-shaped body includes a slot
44 that is shaped and sized to individually receive therein the first and
second toggle switches 30, 32. The second side of the disk-shaped body,
in contrast, has a blocking wall 46, which extends over and physically
obstructs the first or the second engaged position of the first and
second toggle switches 30, 32, respectively.

[0023] Although shown with a single slot 44, the rotary interlock
mechanism 40 can be fabricated with multiple slots 44 without departing
from the intended scope and spirit of the present disclosure. For
example, the rotary interlock mechanism 40 can include two slots 44 that
are offset 90 degrees from each other. By incorporating an additional
slot 44, the rotary interlock mechanism 40 can operate with two
functional pairs of electrical switches, allowing one electrical switch
in each pair to be ON, while preventing one of the electrical switches in
each pair from being moved into an ON position.

[0024] When the rotary interlock mechanism 40 is in the first orientation,
as seen for example in FIG. 2, the first circuit breaker 26 is precluded
from being activated because the blocking wall 46 physically obstructs
the first engaged position thereby preventing the first toggle switch 30
from being moved into the first engaged position. Contrastingly, the
second circuit breaker 28 can be activated when the rotary interlock
mechanism 40 is in the first orientation because the slot 44 receives
therein the second toggle switch 32 allowing the second toggle switch 32
to be moved into the second engaged position. By way of comparison, when
the rotary interlock mechanism 40 is in the second orientation, as seen
for example in FIG. 1, the second circuit breaker 28 is precluded from
being activated because the blocking wall 46 physically obstructs the
second engaged position thereby preventing the second toggle switch 32
from being moved into the second engaged position. In contrast, the first
circuit breaker 26 can be activated when the rotary interlock mechanism
40 is in the second orientation because the slot 44 receives therein the
first toggle switch 30 allowing the first toggle switch 30 to be moved
unimpeded into the first engaged position.

[0025] In the illustrated embodiment, the rotary interlock mechanism 12
can be transitioned between the first and second orientations by turning
the rotary member 40 in the clockwise or the counterclockwise direction.
In some embodiments, the rotary member 40 can be turned in only a
clockwise or a counterclockwise direction. In the illustrated embodiment,
the position of the rotary member 40 relative to the housing 14 remains
unchanged when the rotary member 40 rotates between the different
operating orientations. The design of the rotary interlock mechanism 12
is intended to be intuitive; thus, there is generally no need for
features to align the rotary member 40 with the toggle switches 30, 32.
In some embodiments, however, the rotary interlock mechanism 12 includes
alignment features, such as raised tabs or visual indicators, for
operatively aligning the rotary member 40 with the toggle switches 30,
32.

[0026] The rotary interlock mechanism 12 can be mounted to the electrical
switch assembly 10 in a variety of different ways. In FIG. 1, for
example, the rotary member 40 is rotatably fastened to the housing 14 via
a rivet 42, which is received in a complementary hole in an elongated
mounting bracket 50, which is rigidly mounted to the top wall 16 of the
housing 14. In some applications, the mounting bracket 50 is unnecessary,
and therefore can be eliminated from the rotary interlock assembly. By
way of non-limiting example, FIG. 3 illustrates a representative circuit
breaker assembly, designated generally as 210, with an exemplary rotary
interlock mechanism, designated generally as 212. The circuit breaker
assembly 210 includes a plurality of electrical circuit breakers,
represented herein by first and second circuit breakers 226 and 228,
respectively, that are mounted to a switch panel 124. The first circuit
breaker 226 includes a first toggle switch 230 that is movable between
respective engaged and disengaged positions, while the second circuit
breaker 228 includes a second toggle switch 232 that is movable between
respective engaged and disengaged positions. The rotary interlock
mechanism 212 of FIG. 3 includes a rotary member 240 that is rotatably
mounted to the housing 212 in between the first and second toggle
switches 230, 232. In contrast to the embodiment of FIG. 1, the rotary
member 240 of FIG. 3 is rotatably fastened directly to the switch panel
224, e.g., via a rivet 242. That is, a complementary bore hole (not
visible in the view provided) is fabricated in the switch panel 224. The
buck-tail end of the rivet 224 is passed through the complementary bore
hole in the switch panel 224, and then deformed so that it expands,
holding the rivet in place.

[0027] One or more optional protrusions 48 project from an upper surface
of the rotary member 40. In FIG. 1, for example, the rotary member 40
includes two protrusions 48, each of which is a square-shaped, radially
oriented flange that was stamped out of the disk-shaped body and extends
generally perpendicularly from the rotary member 40. The protrusions 48
facilitate rotating the rotary member 40 between the first and second
orientations by providing gripping surfaces for the operators fingers. In
another example, FIG. 2 illustrates a representative circuit breaker
assembly, designated generally as 110, with an exemplary rotary interlock
mechanism, designated generally as 112. The circuit breaker assembly 110
includes a plurality of electrical circuit breakers, represented herein
by first and second circuit breakers 126 and 128, respectively, that are
mounted to a switch panel 124. The first circuit breaker 126 includes a
first toggle switch 130 that is movable between respective engaged and
disengaged positions, while the second circuit breaker 128 includes a
second toggle switch 132 that is movable between respective engaged and
disengaged positions. The rotary interlock mechanism 112 of FIG. 2
includes a rotary member 140 that is rotatably mounted to the housing 112
in between the first and second toggle switches 130, 132. In contrast to
the embodiment of FIG. 1, the rotary member 140 of FIG. 2 includes two
protrusions 148, each of which is a triangle-shaped, radially offset
flange that was stamped out of and extends generally perpendicularly from
the rotary member 140. In an alternative configuration, the rotary member
240 of FIG. 3 includes a single protrusion 248, which is a rectangular
tab that is mechanically fastened or otherwise attached to the top
surface of the rotary member 240. Alternatively, FIG. 4 illustrates
another exemplary rotary interlock mechanism, designated generally as
312, in accordance with the aspects of the present disclosure. In this
embodiment, the rotary interlock mechanism 312 consists of a disk-shaped
rotary member 340 that is rotatably fastened to a housing bracket 314 via
a single rivet 342. In contrast to FIGS. 1-3, the rotary member 340 of
FIG. 4 includes a single protrusion 348, which is a raised surface that
was stamped out of the disk-shaped rotary member 340.

[0028] The rotary interlock mechanisms disclosed herein are amenable to a
variety of variations and modifications. For example, although
illustrated throughout the drawings as a generally flat, circular
disk-shaped part, the rotary member can take on a variety of alternative
shapes, such as elliptical, polygonal, oblong, etc., and geometries, such
as cylindrical, frustoconical, etc. Moreover, the rotary member can be
operatively attached to the housing by various alternative means, such as
a nut-and-bolt combination, a bushing, a bearing, or a threaded screw. To
that end, the attachment means need not be a separate component, but may
be integrally formed with the rotary member. For example, the rotary
member can be preformed with a male snap-fastener feature that protrudes
from one side of the rotary member. As yet another example, the rotary
member can be modified to replace the slot 44 with a flat edge which
abuts against a respective switch actuator when the switch actuator is
moved into an engaged position.

[0029] An advantage of some of the disclosed aspects is that the rotary
interlock mechanism requires very few parts (as few as two in some
designs), and is therefore inexpensive to manufacture and easy to
install. To that end, the rotary interlock mechanism can be fabricated in
a single punch-and-die operation, which reduces material costs and
minimizes production time and costs. In addition, some designs only
require a single rivet to attach the rotary interlock mechanism to the
switch assembly, further reducing manufacturing costs and simplifying the
assembly process, which in turn reduces assembly time and labor costs.
Another advantage of using a rivet, in comparison with threaded
fasteners, is the reduction in friction between the attachment interface
and the interlock plate, which minimizes the requisite operating force
and, consequently, facilitates the blocking interchange movement.

[0030] Another advantage of some of the disclosed aspects is that the
rotary interlock mechanism features an ergonomic design that minimizes
physical effort and discomfort, and hence maximizes efficiency. For
example, the ergonomic design of the rotary interlock mechanism allots
for a wider tolerance (e.g., margin or error) when changing switches. In
particular, slidably mounted blocking plates require precise alignment of
the plate with the electrical switches for proper operation. In contrast,
some of the disclose aspects merely require the rotary interlock
mechanism be generally aligned with the functionally paired electrical
switches to allow the operator to change active switches. In addition,
operation of the rotary interlock mechanism is intuitive, and therefore
requires no special training, which minimizes the possibility of improper
usage.

[0031] An advantage of some of the disclosed aspects is that the rotary
interlock mechanisms are completely secure, ensuring that blocked
switches are kept disconnected while allowing unblocked switches to be
easily connected. Another advantage is that the rotary interlock
mechanisms minimize the amount of packaging space required to properly
operate. While slidable interlock plates require additional packaging
space to accommodate multiple operating positions, the rotary interlock
mechanism does not change position relative to the housing and therefore
does not require additional packaging space for proper operation. Another
advantage over the prior art is that the some of the disclosed designs do
not require additional tooling or special tooling to properly operate.
Moreover, some designs require special tooling to remove the interlock
mechanism from the switch assembly, ensuring that the interlock mechanism
is secure and cannot be easily tampered with.

[0032] While particular embodiments and applications of the present
disclosure have been illustrated and described, it is to be understood
that the present disclosure is not limited to the precise construction
and compositions disclosed herein and that various modifications,
changes, and variations can be apparent from the foregoing descriptions
without departing from the spirit and scope of the invention as defined
in the appended claims. To that extent, elements and limitations that are
disclosed, for example, in the Abstract, Summary, and Detailed
Description sections, but not explicitly set forth in the claims, should
not be incorporated into the claims, singly or collectively, by
implication, inference, or otherwise.